Why won't my Illumination bar blink for notifications when the screen is off?

hi, I have Sony xperia m2. when the screen is off (I guess it's in a sleep mode) I want to see illumination bar blinking when I get a missed call or sms or whatever.I tried apps like Illumination bar and Light Flow Light but it didn't work. The first one didn't work at all, with Light Flow Light I could change the colors and blinking rate but it only worked when the screen was on. When the screen went black, the blinking stopped and only the small LED light turned on blinking.... Is anything I missed in settings of the phone? It doesn't work when Stamina is off or on. Any suggestions anyone? Maybe I should try another app?